Autolocating underwater beacon and method for deployment thereof

Abstract

An underwater acoustic beacon includes a subsystem for determining geographical position, and a transmitter for transmitting coordinates of the position at the point of impact when the beacon is deployed.

1 . An underwater acoustic beacon characterized in that it includes at least: 
 a device for determining geographical co-ordinates  17 ,    a transmission device for transmitting said co-ordinates  24 ,    a waterproof enclosure  22  supporting an acoustic transducer  18 ,    associated electronics circuitry  19 , and,    a floatation  23 , and an anchoring device  20  of said enclosure.    
   
   
       2 . An underwater acoustic beacon according to  claim 1 , wherein the acoustic transducer ( 18 ) is used in emission and reception.  
   
   
       3 . An underwater acoustic beacon according to  claim 1 , wherein the acoustic emissions are controlled by an ultra stable clock  35 .  
   
   
       4 . An underwater acoustic beacon according to  claim 1 , wherein the acoustic emissions are controlled by an ultra stable clock  35 , and further wherein the clock signal output of a radio positioning receiver  25  is used to synchronize a beacon internal clock  35  to share an absolute reference of time.  
   
   
       5 . An underwater acoustic beacon according to  claim 4 , further comprising means for slowing down or guiding the beacon during its fall, such as an opening airfoil  15 .  
   
   
       6 . An underwater acoustic beacon according to  claim 1 , wherein it has a device  29  for automatically opening the airfoil at low altitude, above water.  
   
   
       7 . An underwater acoustic beacon according to  claim 1 , wherein it has on its periphery a device  42  to reduce its signature with respect to active sonar.  
   
   
       8 . An underwater acoustic beacon according to  claim 1 , wherein the channel of communication  24  of the beacon co-ordinates is a radio link, a communication satellite link, an infra-red or laser channel.  
   
   
       9 . An underwater acoustic beacon according to  claim 1 , wherein the device for determining local geographical coordinates  25  is a satellites positioning receiver (GPS, GLONASS or GALILEO).  
   
   
       10 . An underwater acoustic beacon according to  claim 1 , wherein it integrates a pressure sensor  36  and a means for coding of the emissions for transmitting by acoustic channel telemetry data representing the value of immersion of the beacon and/or its geographical co-ordinates.  
   
   
       11 . A method of deployment of underwater acoustic beacons, comprising the following operations: 
 providing at least one autolocalized underwater acoustic beacons  6  according to  claim 1 ,    loading on board an aircraft  1  inhabited or not one or more of the aforesaid autolocalized underwater acoustic beacons,    dropping said beacons above an underwater mobiles mission area,    memorizing onboard the aircraft  1  the co-ordinates of the beacons as received during the fall  2 , up to the point of impact  4  with water,    releasing  7  an anchoring device  20  allowing positioning the beacon above the sea-bed at a predetermined altitude,    activating the electronic circuits  33  for sequencing the acoustic emissions of the aforesaid beacon, and    downloading in an embedded memory on board underwater mobiles  13  the co-ordinates of the points of impact of the beacons and their particular acoustic characteristics.    
   
   
       12 . A process of deployment of underwater acoustic beacons according to  claim 11 , wherein the means of deployment is not an aircraft; but, a ship  8  or a submarine, with or without crew.  
   
   
       13 . A process of deployment of underwater acoustic beacons, according to  claim 11 , further comprising a relay transmitter, in the compartment of the carrier  1 , for transmitting radio positioning signals to allow the start-up of the radio positioning receiver before dropping of the beacon.  
   
   
       14 . A process of deployment of underwater acoustic beacons according to  claim 11 , wherein the means for determining local geographical co-ordinates is located on board the launcher.  
   
   
       15 . A process of deployment of underwater acoustic beacons according to claims  11 , characterized by the fact that specific buoys, a boat or an underwater vehicle are used at a later stage to improve the precision of localization of beacons once anchored.  
   
   
       16 . A process of deployment of underwater acoustic beacons, according to  claim 12 , further comprising a relay transmitter, in the compartment of the carrier  1 , for transmitting radio positioning signals to allow the start-up of the radio positioning receiver before dropping of the beacon.